1. Field of the Invention
The present invention relates to a shut-off apparatus, including a main body provided with a passage, a disk shaped shut-off flap, a seat located in said passage and intended to cooperate with said shut-off flap, a rocking shaft extending perpendicularly to said passage, which shut-off flap is mounted to said rocking shaft for relative movement thereto in longitudinal direction thereof but positive rotational movement therewith, and including an operating means operative to lift said flap off said seat or to place said flap on said seat, respectively, during one phase of movement, and to rotate said flap in its lifted off position and said rocking shaft in a further phase of movement, and including further drive means for driving said operating means.
2. Description of the Prior Art
Such shut-off apparatus is for instance disclosed in the Swiss patent application no. 6388/82. The shut-off apparatus disclosed in mentioned patent application as well as other shut-off apparatuses presently on the market are provided with operating means which must be controlled at a location outside of the base body, by means of which operating means the two phases of movement of the shut-off flap are carried out by means of a rotational movement.
The drawback of the construction of these known shut-off apparatuses is that the sealing of the operating means against the base body, i.e. against the environment, is insufficient, at least for certain applications of the shut-off apparatus. An absolutely safe gas or liquid-tight seal is not possible.